With farsightedness, or hyperopia eyes focus optical system (the formation of the best images) is behind the retina. This is called refraction refraction still weak in relation to this eye. Ie refraction is too small relative to the anteroposterior size of the eye.
If you reduce the amount of hyperopia the eyeball from front to back, reduced the depth of the anterior chamber, usually a narrow pupil. In such a clear image of the eye would give converging beams, but in the nature of these rays do not exist. In the absence of a clear image of the object on the retina, the mechanism of accommodation is included, which allows you to add the missing eye diopter and move the image of the object on the retina. With further approximation, subject to the eye, with the degree of hypermetropia accommodation should be increased to a greater extent than in eyes with normal refraction. Therefore, hyperopia reserve accommodation ends earlier, and before there is presbyopia and its correction needed stronger lenses.
A patient with hyperopia without accommodation see clearly objects at any distance, and when approaching an object to the eye, vision is deteriorating. At closer distances the rays from the objects of the environment are divergent and hyperopic eyes focus them even harder than the parallel rays from infinity. It takes extra effort to accommodate. The term farsightedness due to the fact that a patient sees in the distance is still better than up close.
Sighted person can hold the text very close to the eye, because it increases the image of the text on the retina. However, the image is not getting better, it just increased. The patient often squints, trying to help the accommodation, which may contribute to the development of blepharitis and conjunctivitis, along with a constant voltage of the ciliary muscle.
In continuous operation in the vicinity of hyperopia may have complaints of fatigue, sore eyes, headaches, watery eyes, burning eyes, stinging the eyes. Could cause discomfort when looking at the light or intolerance to bright light. This is called accommodative asthenopia. Accommodative asthenopia the more pronounced the greater the degree of hyperopia.
Hyperopia is of three degrees and is determined by the number of diopters, which lack the hyperopic eye, that would be emmetropic:
hyperopia of weak degree - up to 2.0 diopters
moderate hyperopia - up to 4.0 diopters
hypermetropia of high degree - more than 4.0 diopters.
In the hyperopic eye with a low degree of accommodation by doing its job. And with hyperopia medium and high degree of correction required and given, and for close distances.
Correction of hyperopia when performed by ophthalmic glasses, contact lenses and surgical techniques. Correction should be performed in a timely manner, especially in children. This prevents the development of complications of hyperopia:
amblyopia (reduced vision in the worse seeing eye)
early development of presbyopia.
Selection of lenses perform on each eye separately. Contact lenses have several advantages over sunglasses. They do not restrict the field of view, providing a good view when you turn the eyeballs, invisible to others. However, when wearing them can develop idiosyncrasy. If any of the use of contact lenses may experience inflammatory diseases of the mucous membranes of the eyes.
For surgical correction of hyperopia include:
hexagonal keratotomy (holding deep cuts in the 6 mm from the center of the cornea)
Deep thermocoagulation (point on the periphery of the cornea coagulants) hypermetropic autokeratoplastika (implantation autobiolinzy under truncated portion of the anterior corneal surface).
Sometimes at high degrees of hypermetropia hypermetropic keratomileusis applied. At the same time cut off small sections of the cornea, after which the corneal tissue in this area intensively regenerates and increases its refractive power.
In some cases, solve the problem of presbyopia in adults can be achieved by the operation of laser vision correction
At the current time the most modern surgical methods of treatment are: Excimer photorefractive keratotomy
Laser specialized keratomileusis.
Hyperopia, Correction of hyperopia, surgical correction of hyperopia